Surface Morphology and In Vitro Bioactivity of Biocompatible Hydroxyapatite Coatings on Medical Grade S31254 Steel by RF Magnetron Sputtering Deposition

Hydroxyapatite (HA) is popularly used as a bio-compatible coating material for metallic implants, in view of its improved bone fixation property, leading to an increased life of the implant. However, the deposition of HA on medical grade UNS S31254 stainless steel (SS254) for orthopaedic implant applications by the radio-frequency magnetron sputtering technique is unreported in the literature so far. The surface morphology of deposited HA coatings was characterized using Scanning Electron Microscopy and Atomic Force Microscopy, while their phase composition was determined using X-ray Diffraction. The thickness and adhesive strength of the HA coatings were determined using an Ellipsometer and a Tensometer, respectively. Finally, the antibacterial efficacy and bioactivity of the deposited coatings were confirmed using Fluorescence Activated Cell Sorting and Immersion test in Simulated Body Fluid environment. The obtained results showed that the HA coatings grown on SS254 using magnetron sputtering possess desirable surface properties as well as adhesion and biocompatibility properties, ideally suited for potential applications in orthopaedic implants.